1. Field of the Invention
This invention relates to capacitors particularly solid electrolytic capacitors.
2. Description of the Prior Art
Solid electrolytic capacitors have sintered metal-powder slugs or foil anodes which have been subjected to an oxidation process--for example electrolytic anodization--to form a homogenous oxide film over the complete surface of the metal, and which provides the dielectric of the capacitor. In powder metal anodes a mass of powdered valve metal, usually tantalum, is compacted in a die and sintered to provide an individual anode. This method, unless expensive duplication of dies is undertaken, does not allow more than one anode to be made at a time.
A technique for screen-printing porous tantalum pads onto a tantalum substrate to make tantalum chip capacitors is described in the Proceedings of the 28th Electronic Components Conference, Anaheim, CA, pp. 422-426. The screen-printed substrate is sintered, anodized and then electrode connections are established. All processing including encapsulation is carried out before the substrate is finally diced to yield the individual capacitor.
Leadless capacitors can be manufactured according to this technique.